[U-Boot] [PATCH resend] armv7/ltimer: Add support for local timer on armv7 cpus

Vipin Kumar
2012-12-06T09:22:55Z

Certain ARMV7 cpus eg. CortexA9 contains a local and a global timer within the
CPU core itself. This patch adds generic support for local timer.

Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
---
arch/arm/cpu/armv7/Makefile | 11 ++-
arch/arm/cpu/armv7/ca9_ltimer.c | 152 ++++++++++++++++++++++++++++++++++++++
arch/arm/include/asm/ca9_ltimer.h | 40 ++++++++++
3 files changed, 199 insertions(+), 4 deletions(-)
create mode 100644 arch/arm/cpu/armv7/ca9_ltimer.c
create mode 100644 arch/arm/include/asm/ca9_ltimer.h

diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile
index 4fdbee4..3ef01f6 100644
--- a/arch/arm/cpu/armv7/Makefile
+++ b/arch/arm/cpu/armv7/Makefile
@@ -27,15 +27,18 @@ LIB = $(obj)lib$(CPU).o

START := start.o

-COBJS += cache_v7.o
+COBJS-y += cache_v7.o

-COBJS += cpu.o
-COBJS += syslib.o
+COBJS-y += cpu.o
+COBJS-y += syslib.o
+COBJS-$(CONFIG_ARMV7_CA9LTIMER) += ca9_ltimer.o

ifneq ($(CONFIG_AM33XX)$(CONFIG_OMAP44XX)$(CONFIG_OMAP54XX)$(CONFIG_TEGRA20),)
-SOBJS += lowlevel_init.o
+SOBJS-y += lowlevel_init.o
endif

+COBJS := $(sort $(COBJS-y))
+SOBJS := $(sort $(SOBJS-y))
SRCS := $(START:.o=.S) $(COBJS:.o=.c)
OBJS := $(addprefix $(obj),$(COBJS) $(SOBJS))
START := $(addprefix $(obj),$(START))
diff --git a/arch/arm/cpu/armv7/ca9_ltimer.c b/arch/arm/cpu/armv7/ca9_ltimer.c
new file mode 100644
index 0000000..cbf1552
--- /dev/null
+++ b/arch/arm/cpu/armv7/ca9_ltimer.c
@@ -0,0 +1,152 @@
+/*
+ * (C) Copyright 2012
+ * Vipin Kumar, ST Micoelectronics, vipin.kumar at st.com.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/ca9_ltimer.h>
+#include <asm/arch/hardware.h>
+
+#define READ_TIMER() readl(&ca9_timer_p->count)
+
+static struct ca9_timer_regs *const ca9_timer_p =
+ (struct ca9_timer_regs *)CONFIG_ARMV7_LTIMER_BASE;
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define timestamp gd->tbl
+#define lastdec gd->lastinc
+#define tickshz gd->timer_rate_hz
+#define ticksper10usec gd->tbu
+
+int timer_init(void)
+{
+ u32 prescaler, timertickshz;
+ /*
+ * Genrally, CortexA9 MPUs are operating from 500MHz to 1500MHz which
+ * means that CA9 local timer clock would be in the range of 250 MHz to
+ * 750MHz.
+ * Try to find a prescaler which can perfectly divide the local timer
+ * clock. Take prescaler as 200 if nothing is found
+ */
+ for (prescaler = 255; prescaler > 1; prescaler--) {
+ if (CONFIG_ARMV7_LTMR_CLK ==
+ (CONFIG_ARMV7_LTMR_CLK / prescaler) * prescaler)
+ break;
+ }
+
+ if (prescaler == 1)
+ prescaler = 200;
+ timertickshz = CONFIG_ARMV7_LTMR_CLK / prescaler;
+ ticksper10usec = timertickshz / (100 * 1000);
+ tickshz = timertickshz / CONFIG_SYS_HZ;
+
+ /* disable timers */
+ writel(((prescaler - 1) << 8) | AUTO_RELOAD, &ca9_timer_p->control);
+
+ /* load value for free running */
+ writel(FREE_RUNNING, &ca9_timer_p->load);
+
+ /* auto reload, start timer */
+ setbits_le32(&ca9_timer_p->control, TIMER_ENABLE);
+
+ reset_timer_masked();
+
+ return 0;
+}
+
+/*
+ * timer without interrupts
+ */
+
+void reset_timer(void)
+{
+ reset_timer_masked();
+}
+
+ulong get_timer(ulong base)
+{
+ return (get_timer_masked() / tickshz) - base;
+}
+
+void set_timer(ulong t)
+{
+ timestamp = t;
+}
+
+void __udelay(unsigned long usec)
+{
+ ulong tmo;
+ ulong start = get_timer_masked();
+ ulong rndoff;
+
+ rndoff = (usec % 10) ? 1 : 0;
+ tmo = ((usec / 10) + rndoff) * ticksper10usec;
+
+ while ((ulong) (get_timer_masked() - start) < tmo);
+}
+
+void reset_timer_masked(void)
+{
+ /* reset time */
+ lastdec = READ_TIMER();
+ timestamp = 0;
+}
+
+ulong get_timer_masked(void)
+{
+ ulong now = READ_TIMER();
+
+ if (now <= lastdec) {
+ /* normal mode */
+ timestamp += lastdec - now;
+ } else {
+ /* we have an overflow ... */
+ timestamp += lastdec + FREE_RUNNING - now;
+ }
+ lastdec = now;
+
+ return timestamp;
+}
+
+void udelay_masked(unsigned long usec)
+{
+ return udelay(usec);
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+ return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+ return CONFIG_SYS_HZ;
+}
diff --git a/arch/arm/include/asm/ca9_ltimer.h b/arch/arm/include/asm/ca9_ltimer.h
new file mode 100644
index 0000000..8833853
--- /dev/null
+++ b/arch/arm/include/asm/ca9_ltimer.h
@@ -0,0 +1,40 @@
+/*
+ * (C) Copyright 2012
+ * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef __ARCH_ARM_CA9TIMER_H
+#define __ARCH_ARM_CA9TIMER_H
+
+struct ca9_timer_regs {
+ u32 load;
+ u32 count;
+ u32 control;
+};
+
+/* control related definitions */
+#define AUTO_RELOAD (1 << 1)
+#define TIMER_ENABLE (1 << 0)
+
+/* load related definitions */
+#define FREE_RUNNING (0xFFFFFFFF)
+
+#endif
--
1.8.0